Hi Gwen, Lucky you - Danielle is teaching a class on that very subject. Here's the link: Power of the Press Release: How to get your story covered by the media.
I attended her last one, and it rocked.
To specifically answer your question, though... I'd recommend including the full text of your release in the body of an email to a specific journalist at the media outlet you are targeting. You can also include an attachment with fancier formatting, but if you only include the attachment they might never open it. It should be something they can read at a glance.

